Linear motor conveyor system with diverter and method for design and configuration thereof

ABSTRACT

A linear motor conveyor system having a moving element comprising a first and a second magnetic element on opposite sides; a first track comprising a first linear motor configured to generate a dynamic magnetic field which acts on the first magnetic element to provide a first dynamic lateral force and a first dynamic longitudinal force; a second track with a transfer region adjacent to the first track, the second track configured to generate a magnetic field that acts on the second magnetic element to provide a second lateral force; and a controller to control the first linear motor such that the first dynamic lateral force is configured to bias the moving element toward the first linear motor until the moving element reaches a switch point in the transfer region, after which the dynamic lateral forces are selectively adjusted to bias the moving element toward the first or second track.

RELATED APPLICATIONS

The application is a continuation of PCT Application No.PCT/CA2018/050263, filed Mar. 6, 2018 which claims priority to U.S.patent application Ser. No. 62/467,357 filed Mar. 6, 2017, which arehereby incorporated herein by reference.

FIELD

The present disclosure relates generally to a conveyor system andbearing system for supporting moving elements thereon and, moreparticularly, a conveyor system having a transfer or divert section forbranching, merging, diverting, or otherwise transferring moving elementsfrom one track to another track.

BACKGROUND

In conventional linear motor systems, a moving element is controlled tomove along a track by electromotive force. In a moving magnet linearmotor, the moving element generally includes a permanent magnet and thetrack includes an electromagnetic field generator. The moving element isplaced on the track such that the magnet is acted on by theelectromagnetic field in order to move the moving element along thetrack. In some cases, the moving element may have bearings which runalong the track and the moving element is supported by guides or guiderails or the like on the track. The guide rails may, for example, engagewith the bearings or with the moving element itself. The bearings mayinclude plain bearings, ball bearings, needle bearings, roller bearings,wheel bearings and the like.

In linear motor systems, forces, including acceleration, on the movingelement can be high in order to move or stop the moving element quicklyin order to increase production speeds. In this environment, the movingelement may require larger or enclosing guide rails to help tocounteract the forces. It is generally important that the moving elementmaintain an accurate, stable trajectory without unintentionallyseparating from the track. As such, in conventional systems, it can bedifficult to remove, divert, branch or transfer off the moving elementsfrom the track either because of the forces of magnetic attraction, orbecause of bearing engagement with the track or enclosing guide rails.

In conveyor systems and, in particular, linear motor conveyor systems,conventional bearings may have difficulty in achieving high precision,accurate, and repeatable movement along the direction of motion. Factorsthat may cause variability in precision include i) componentmanufacturing tolerances, ii) backlash or play (e.g. the clearancecaused by gaps between components or parts), iii) how well the bearingsare seated on the guide rail datum surfaces, and iv) the accuracy of themoving element position measuring system. Further, in some cases,conventional bearings may have specific parallelism tolerances and maybe prone to binding during movement. Still further, conventionalbearings often need to be preloaded by preloading hardware and havepreloading adjustments to ensure the bearings stay in positive contactwith the guide rails.

In some conventional bearing systems, as noted above, guide rails areprovided to physically engage with either the moving element or thebearings in order to provide stability. These conventional bearingsystems typically require mechanical disassembly of either or all of themoving element, the bearings, or the guide rails in order to remove themoving element from the track. These types of systems may also requirepreloading or tight manufacturing tolerances on the guide rails andbearings in order to achieve precise movement and positioning and avoidbinding.

In such an environment, it can be difficult to provide a linear motorsystem that allows for track transferring, branching or diverting ofmoving elements from one track to another. As such, there is a need fora linear motor conveyor that provides transferring/branching/divertingthat overcomes at least one problem with conventional systems.

It is a therefore desirable to provide a conveyor system with theability to divert moving elements and provide moving elements for usetherefore.

SUMMARY

According to one aspect herein, there is provided a linear motorconveyor system having a moving element comprising a first magneticelement on a first side and a second magnetic element on a second side,opposite to the first side; a first track comprising a first linearmotor, the first linear motor configured to generate a dynamic magneticfield which acts on the first magnetic element to provide both a firstdynamic lateral force and a first dynamic longitudinal force on themoving element; a second track with at least a transfer region of thesecond track positioned adjacent the first track, the second trackconfigured to generate a magnetic field that acts on the second magneticelement to provide a second lateral force on the moving element; and acontroller to control at least the first linear motor such that thefirst dynamic lateral force from the first linear motor and the secondlateral force from the second track are configured to bias the movingelement toward the first linear motor until the moving element reaches aswitch point in the transfer region, after which the dynamic lateralforces are selectively adjusted to bias the moving element toward thefirst track or the second track.

In some cases, the first track may include a first magnetic materialwhich acts on the first magnetic element to provide a first staticlateral force in addition to the first dynamic lateral force, whereinthe controller adjusts the lateral force in addition to the firstdynamic lateral force.

In some cases, the second track may include a second magnetic materialwhich acts on the second magnetic element to provide a second staticlateral force, and wherein the controller selectively adjusts the firstdynamic lateral force to bias the moving element toward the first trackor the second track by overcoming net static forces from the first andsecond static lateral forces.

In some cases, the first static lateral force may be set based on afirst magnetic gap between the moving element and the first linearmotor, and the second static lateral force is set based on a secondmagnetic gap between the moving element and the second linear motor.

In some cases, the second track may include a second linear motor.

In some cases, the second magnetic element on the second side of themoving element may be a ferromagnetic element.

In some cases, the second track may include at least one permanentmagnet and the first longitudinal force is configured to propel themoving element along the second track while held to the second track bythe lateral forces of the at least one permanent magnet.

In some cases, the second track may include at least one electromagnetand the first longitudinal force is configured to propel the movingelement along the second track while held to the second track by thelateral forces of the at least one electromagnet.

In some cases, the second track may include a curved track section withan integrated straight profile.

In some cases, the moving element further may include a stabilizerconfigured to reduce rotation of the moving element.

In some cases, the moving element further may include at least one coverfor at least one of the magnetic elements to shield the magnetic field.

In another aspect there is provide a linear motor conveyor systemincluding: a first track comprising a first linear motor; a second trackcomprising a second linear motor with at least a predetermined portionof the second track positioned adjacent the first track; a movingelement comprising a first magnetic element on a first side and a secondmagnetic element on a second side, opposite to the first side, whereinthe first magnetic element and first track are configured such that themoving element is biased toward the first track by a first lateral forceand moved along the first track by a first longitudinal force; and acontroller to control the first and second linear motors such that thesecond linear motor generates a second longitudinal force on the secondmagnetic element and any second lateral force generated by the secondlinear motor that is less than the first lateral force, wherein thesecond linear motor is configured to provide increased thrust to themoving element.

In some cases, the moving element further may include a stabilizerconfigured to reduce rotation of by the moving element.

In yet another aspect, there is provided a linear motor conveyor systemincluding: a moving element comprising at least one magnetic element; afirst track comprising a first linear motor, the first linear motorconfigured to have a first predetermined magnetic gap between the firstlinear motor and the moving element; a second track having at least atransfer region positioned adjacent the first track such that the movingelement has a second predetermined magnetic gap between the second trackand the moving element; and a controller to control the first linearmotor such that, in the transfer region, the first linear motor can beselectively adjusted to generate a lateral magnetic force that overcomesthe difference in magnetic gap and the moving element is biased towardeither the first track or the second track.

In some cases, the second predetermined magnetic gap may be differentfrom the first magnetic gap.

In some cases, the second track may include a second linear motor.

In some cases, the moving element may include a first magnetic elementon a first side and a second magnetic element on a second side, oppositeto the first side.

In some cases, the second magnetic element on the second side may be aferromagnetic element.

In some cases, the second track may include at least one permanentmagnet and the first linear motor is configured to provide sufficientlongitudinal force to propel the moving element along the second trackwhile held to the second track by the lateral forces of the at least onepermanent magnet.

In some cases, the second track may include at least one electromagnetand the first longitudinal force is configured to propel the movingelement along the second track while held to the second track by thelateral forces of the at least one electromagnet.

In some cases, the second track may have a curved track section with anintegrated straight profile.

In some cases, the moving element may further include a stabilizerconfigured to reduce rotation of the moving element.

In some cases, the moving element may further include at least one coverfor at least one of the magnetic elements to shield the magnetic field.

In still yet another aspect, there is provided a moving element for alinear motor conveyor system, the moving element including: at least onemagnetic element having a magnetically calibrated position in relationto the moving element and configured to interact with both a firstlinear motor on a first track and a magnetic field associated with asecond track.

In some cases, the moving element may include a magnet positioningdevice for adjusting position of the magnetic element.

In some cases, the at least one magnetic element may include a firstmagnetic element on a first side and a second magnetic element on asecond side, opposite to the first side.

In some cases, the second magnetic element on the second side may be aferromagnetic element.

In some cases, the moving element may include a stabilizer configured toreduce rotation of the moving element.

In some cases, the moving element may include at least one cover for atleast one of the magnetic elements to shield the magnetic field.

In another aspect, there is provided a setup tool for a linear motorconveyor system, the setup tool including: a body; a magnetic elementprovided to the body; a load cell connected to the magnetic element andconfigured to sense the forces acting on the magnetic element; and acontroller for reading data sensed by the load cell.

In some cases, the setup tool may include bearings provided to the bodyand configured to interact with rails on the linear motor conveyor.

In yet another aspect, there is provided a method of configuring adiverter on a linear motor conveyor system, the method including:physically mounting a first linear motor track adjacent a second trackat a predetermined distance; determining the magnetic forces on a setuptool placed between the adjacent tracks; and adjusting a magnetic setpoint for each of the first and second tracks based on the determinedmagnetic forces to allow a moving element to be diverted from the firsttrack to the second track.

In still yet another aspect, there is provided a method of designing alinear motor conveyor system, the method including: determining thedimensions of at least a straight section and an orthogonal section oftrack; creating a grid based on the determined dimensions; andconfiguring the linear motor conveyor system on the grid such that themoving elements are placed on the grid lines.

In some cases, the method of designing a linear motor conveyor systemmay further include determining dimensions of a 180-degree curvedsection that fits on the grid.

Other aspects and features of the present disclosure will becomeapparent to those ordinarily skilled in the art upon review of thefollowing description of specific embodiments in conjunction with theaccompanying figures.

BRIEF DESCRIPTION OF FIGURES

Embodiments of the present disclosure will now be described, by way ofexample only, with reference to the attached Figures.

FIG. 1 illustrates a conveyor with a divert or transfer sectionaccording to an embodiment;

FIG. 2A illustrates a partial cross-section of a moving element for usein a conveyor with a divert section according to an embodiment;

FIG. 2B illustrates the moving element of FIG. 2A without the partialcross-section;

FIG. 3 illustrates another embodiment of a moving element;

FIG. 4 illustrates an embodiment of a linear motor conveyor using twotrack sections to provide additional thrust to a moving element;

FIG. 5 illustrates a magnetic field protection system for use in aconveyor system according to an embodiment;

FIG. 6 illustrates a divert track section with permanent magnetsaccording to an embodiment;

FIG. 7 illustrates a force diagram on a moving element in a conveyorsystem;

FIGS. 8A and 8B illustrate a setup tool for use in a conveyor systemwith a divert section according to an embodiment;

FIG. 8C illustrates an overhead view of the setup tool when used in aconveyor system according to an embodiment;

FIGS. 9A and 9B illustrate a front perspective view and rear perspectiveview of a stationary setup tool according to an embodiment;

FIG. 10 illustrates an exploded view of a moving element showing amagnet positioning device according to an embodiment;

FIGS. 11A and 11B illustrate a top view and perspective view of aconveyor with divert according to an embodiment;

FIGS. 12A and 12B illustrate example embodiments of track sections forvarying from one height to another;

FIG. 13 illustrates a conveyor with divert;

FIG. 14 illustrates an alternative embodiment of a conveyor with divertas arranged on a grid;

FIG. 15A illustrate another embodiment of a moving element;

FIGS. 15B and 15C illustrate side and cross-sections of the movingelement of FIG. 15A in association with a track section; and

FIG. 16 illustrates yet another embodiment of a moving element.

DETAILED DESCRIPTION

Generally, the present disclosure relates to a conveyor system with atransferring, branching or divert function and a moving elementtherefor.

As noted above, conventional bearings on traditional moving elements areoften engaged onto a guide rail or track and require disassembly to beremoved from the linear conveyor system. These traditional movingelements are generally unable to be reliably diverted because of thisengagement. Further, most linear motor conveyors make use of strongmagnetic attraction in addition to having engaged bearing systems inorder to have better control over the motion of the moving element.Overcoming the magnetic attraction while having the moving elementremain stable and in contact with the guide rail or track has been shownto be difficult using conventional methods unless wheel encapsulation orother similar additional support is provided to the moving element. Assuch, generally, it is difficult to provide a divert function on aconventional linear motor conveyor system. Even if it could beimplemented, such a divert function would typically require significantadditional parts, such as mechanical parts or the like, which may becomecostly, take more space, reduce reliability and constrain theflexibility of the conveyor system.

FIG. 1 illustrates a conveyor system 100 having a track section 102 anda divert section 103 adjacent to the track section 102 (e.g. so that thesections 102, 103 are laterally opposite to each other). In thisdocument, the term “track section” refers to a portion of track that mayeither be a stand-alone module or may be a part of a longer track. Theterm “divert section” is used to refer to a track section onto which amoving element is diverted but it will be understood that movingelements can generally be diverted from any track section to any othertrack section on which there is sufficient room to provide the divertersystem. The conveyor system includes one or more moving elements 104(four are illustrated) which are configured to ride or travel along thetrack section or the divert section. Some of the principles of operationof a linear motor track section such as those described herein areincluded in more detail in U.S. Pat. No. 8,397,896 to Kleinikkink etal., which is hereby incorporated herein by reference.

As noted above, the conveyor system 100 can be composed of a pluralityof track sections 102 which are mechanically self-contained andseparable from one another so as to be modular in nature. In thisembodiment, the track sections 102 are mounted on a support (not shown)so as to align and abut one another in order to form a longer track. Inorder to be modular, each track section 102 may house self-containedelectronic circuitry for powering and controlling the track section 102.The conveyor system 100 may include curved track sections and curveddivert sections.

In FIG. 1, the track section includes a drive motor or element thatproduces a dynamic magnetic force for moving the moving element 104along the track section. The dynamic magnetic force can also assist withsupporting the moving element 104 on the track section. Magneticelements (such as an element generating a magnetic field, or an elementattracted to a magnet, for example a ferromagnetic element or the like,for example, permanent magnets, electromagnetic coils, metal plates orthe like) provided to the moving elements also hold/support the movingelements to the track due to the magnetic attraction of the permanentmagnets to the track (for example, iron laminations within the motor andthe like). For example, the track may be of ferromagnetic materialconfigured to provide a static lateral force (sometimes referred to aspassive lateral force) attracting the moving element toward the track.These static lateral forces are distinguished from the dynamic forces(e.g. forces generated between the moving element 104 and theelectromagnetic coils of the drive motor). For instance, the staticlateral force is present even if no electrical current is passed throughthe electromagnetic coils.

The dynamic magnetic force for moving the moving element is created bythe interaction of the magnetic flux created by magnetic flux elements(for example, embedded coils) (not shown) of the track section andmagnetic elements of the moving element 104. The dynamic magnetic forcecan be thought of as having a dynamic motive force component fordirecting movement of the moving element 104 along an X axis (directionof travel) on the track 106, and, in some cases, a dynamic capturingforce component to hold, on a Y axis (laterally), the moving element 104on the track 106. In practice, the dynamic motive force and the dynamiccapturing force may be provided by the same magnetic flux elements inthe track.

In this embodiment, the track section includes a first guide rail and asecond guide rail configured to support the moving element 104. In oneparticular embodiment, the first guide rail 108 supports the movingelement 104 vertically and horizontally. The first guide rail 108 mayhave at least one “V” shaped profile to support and guide the movingelement 104 on the track 106. In some cases, the moving element mayinclude offset bearings and the first guide rail may have two “V” shapedprofiles to support and guide the moving element. The second guide rail109 supports the moving element 104 horizontally. The second guide rail109 may be a smooth surface with a flat profile.

The first and second guide rails are designed such that the movingelement 104 may be removed/separated from the track section when themagnetic force is overcome.

The magnetic force is overcome, for example, at a divert section 103wherein the magnetic forces operating on the moving element are adjustedin one or both of the track section 102 and the divert section 103 suchthat the moving element transitions from the track section 102 to thedivert section 103. It will be understood that the adjustment of thedynamic magnetic force may involve a change in the magnetic force (forexample, a weakening) at the track section and/or a corresponding change(for example, a strengthening) in the magnetic force at the divertsection over a predetermined distance of travel such that the movingelement is released from the track section and retained/captured by thedivert section. In this way, the moving element 104 can transition fromthe track section and continue on the divert section.

FIGS. 2A and 2B shows an example embodiment of a moving element 104 thatis provided with magnetic elements 128 located on either lateral side ofthe moving element (shown with a cut-away view to illustrate themagnetic elements on each side). In some cases, the magnetic elements128 may provide a magnetic flux that corresponds to or interacts withthe magnetic flux created by of the track section. In other cases, themagnetic elements 128 may be attracted to the magnetic flux created bythe track section. In some embodiments, the magnetic elements 128 may bepermanent magnets, in other embodiments the magnetic elements may beelectromagnets, ferromagnetic elements, or the like. In someembodiments, having magnetic elements on either lateral side of themoving element may help allow the moving element to either divert to adivert section or to continue on a track section depending on thedynamic or static magnetic forces applied from the track section and/ordivert section. The cumulative magnetic forces interacting with themagnetic elements 128 on either side of the moving element may providefor balancing the static lateral magnetic forces in order to enablediversion using the dynamic magnetic forces.

The moving elements may be held to the track by a magnetic force by forexample a permanent magnet and the attraction to the ferromagneticmaterial of the track. These static magnetic forces can be quite largeand may range from 100 N to 4000 N per moving element. The staticmagnetic forces are overcome in order to divert the moving element 104between the track sections. Having magnetic elements 128 on either sideof the moving element 104 may provide for balancing of the static forceswhich is intended to allow for diversion using dynamic magnetic forces,for example, via field strengthening and/or field weakening forces.

A controller (101 in FIG. 1), including a processor and memory, may beused to adjust the magnetic fields produced by the track section anddivert section on the conveyor system to ensure that the moving element104 is moved along the appropriate section. In some embodiments, theremay be a single magnetic element, for example, embedded in the movingelement between the two lateral sides, either at the center or offset.

As shown in FIGS. 2A and 2B, the moving element 104 has a first set ofbearings 124 and a second set of bearings 126. In this embodiment, thefirst set of bearings 124 is located above the second set of bearings126. The first and second set of bearings 124, 126 may be wheel bearingsthat are rotatably attached to the moving element 104.

The first set of bearings 124 rides on the first guide rail. The firstset of bearings 124 has an edge profile that corresponds to the profileof the first guide rail. In an embodiment, the first set of bearings 124has a “V” shaped profile that matches the opposite “V” shape profile ofthe first guide rail 108. In some cases, as shown in FIG. 2B, thebearings of the first set of bearings 124 may be offset and adapted tomatch a dual shaped first guide rail. In other cases, the bearings maybe aligned. The first set of bearings 124 may alternately have a “U”shaped profile or another appropriately shaped profile. The shaped guiderails and bearings are intended to support the moving element 104 alonga Z axis that is perpendicular to the X and Y axes (in this case, thevertical axis). In some cases, the moving element 104 has two bearingsin the first set of bearings 124 but additional bearings may beincluded. In certain cases, the two bearings in the first set ofbearings may be offset or in-line.

The second set of bearings 126 rides on a second guide rail. The secondset of bearings 126 has an edge profile that corresponds to the profileof the second guide rail. In an embodiment, the second set of bearings126 has a flat profile (e.g., a flat wheel) that matches the flatprofile of the second guide rail. The second set of bearings 126 mayroll within a range (slightly higher or lower) on the second guide railto adapt to any non-parallelism with the first guide rail. In somecases, the second set of bearings 126 includes a plurality of bearings,for example, the set could include two or more flat wheels. In certaincases, the bearings within the second set of bearings may be offset fromeach other, for example, to allow overlap with another moving element orthe like.

Higher precision may be achieved over conventional conveyors bysupporting the moving element 104 with magnetic force and the first setof bearings 124 to control the moving elements 104 along the Y axis andthe Z axis including position and rotation. In certain cases, the firstset of bearings 124 maintains the moving element 104 along the Y axisand the Z axis and assists with controlling pitch rotation (about the Yaxis) and yaw rotation (about the Z axis). The first set of bearings 124is also intended to aid in precise movement and positioning along the Xaxis.

The second set of bearings 126 assist with controlling rotation of themoving element 104 about the X axis. The second set of bearings 126 maybe positioned at a distance from the guide rail 108 to minimizevariability due to rotation about the X axis that may be experienced bya pedestal 138 which supports a work surface. The bearings 126 and theguide rail 109 may have tight tolerances on the dimensions that impactrotation about X axis to allow precise positioning of the moving element104.

FIG. 3 shows an alternative embodiment of a moving element 204 in whichthere is a single magnetic element 228 provided to the moving element.In this case, as with other embodiments, the magnetic element may be apermanent magnet, an array of permanent magnets, an electromagnet or thelike. In this embodiment, the magnetic element is provided at a centralportion of the moving element and may, in some cases, be mounted or maybe internal to the body of the moving element. The moving element isconfigured such that the magnetic element can be acted on by either orboth of the track section and the divert section from either side of themoving element. In some cases, the magnetic element may be offset by apredetermined amount to one side such that the moving element will begenerally biased toward one side during movement. This may help tobalance the magnetic forces during a transfer, for example a merge ordivert between track sections.

It is intended that a divert section may be added anywhere along thelinear motor without the need of additional magnets, coils, electronicsor mechanical parts on the track section or the divert section to assistin the diversion of the moving element. The moving element may be lowmass, compact and cost effective. As the moving elements 104, 204 haveopen, non-constrained bearings, the moving elements 104, 204 areintended to be free to pass from a track section to a divert sectionbased on an adjustment in the magnetic field (static, dynamic, or both)on either or both of the track section and divert section as describedherein.

In some embodiments, as shown in FIG. 4, a linear motor conveyor system300 may, instead of providing for a divert or in addition to a divert,use two track sections 302 arranged opposite each other to provide for adual motor thrust to a moving element such as that shown in FIGS. 2 and3. In particular, conveyor systems may have areas where high speed andhigh throughput is preferable, for example using the dual thrust withtwo opposing track sections, while other locations may require lower orslower performance, for example using a single track section. In somecases, it may be beneficial to provide an ability to increase thrust atpredetermined locations along a linear motor conveyor system. Theability to increase thrust is intended to be cost effective and compact.In a particular embodiment using the moving element 104 which includes amagnetic element on either side of the body of the moving element, theconveyor system may include an additional linear motor that isconfigured to act on the second set of magnetic elements in regionswhere increased speed or throughput would be beneficial. In thissituation, the track section providing the additional thrust may beconfigured such that there is a bigger gap between the motor and themagnetic element so that there is a lower lateral force pulling themoving element toward the additional thrust track section.Alternatively, the hardware or software controllers could reduce thelateral force from the additional thrust track section. Further, theadditional thrust track section may be controlled such that forces arereduced as the moving element exits the additional thrust track section.In some embodiments, the two opposing track sections may be capable ofproviding thrust to a moving element having a single magnetic element.

FIG. 5 illustrates a magnet cover for a conveyor system that can be usedin a situation when additional magnetic fields (for example, from asecond magnetic element on a back/opposite side of a moving element) arenot required. As described herein, the moving element 104 may have dualmagnets (one on each side of the moving element) for diversion and/oradded thrust. In some regions of the track, the second set of magneticelements may not be used but remain exposed. The second set of magneticelements may continue to generate static magnetic fields that may beprone to attract magnetic materials or may otherwise become problematicfor the travelling moving element. A magnetic cover 350 may be used toreduce the static magnetic fields that are being emitted from the movingelement. The cover 350 may be attached to the moving element itself or,as shown in FIG. 5, attached to the conveyor system in regions that arenot being used for diversion, for added thrust or the like. In someembodiments, the cover may be removable or may be adapted to be movablebetween a position where it is active (i.e. reducing the field) orinactive (i.e. not reducing the field in the same way).

Preferably, the cover would be kept at an appropriate distance from themagnetic elements in order to minimize drag and heat generation that maybe created in the covered region. The cover may be a material thatreduces the emitted magnetic field to a lower level beyond the cover350. The cover 350 is intended to provide adequate coverage to reduce orprevent the risk of magnetic materials being attracted to, for example,the second set of magnetic elements on the moving element 104. In othercases, the cover may be of non-ferromagnetic material and may provideprotection from external ferromagnetic materials attracting to themagnetic elements of the moving element.

In other cases, one of the magnetic elements may be a ferromagneticplate while a magnetic element that generates a magnetic field may beused on the other side of the moving element. In some cases, a cover maynot provide adequate coverage for the emitted magnetic field dependingon, for example, the products being conveyed, the sterile or cleannature of the conveyor system, or the like. Using a ferromagnetic platemay allow for a lateral attraction force at a divert section without theadditional emitted magnetic field provided by two magnetic elements. Inthis case, permanent magnets may be applied to, for example, cornerdivert locations, that may provide sufficient attraction forces todivert the moving element by attracting the ferromagnetic plate to thepermanent magnets.

In an example, a biasing of the moving element may be accomplished byreplacing the second set of magnetic elements with a ferromagnetic plateand having permanent magnets on a divert section guide rail, rather thanelectromagnetic coils. FIG. 6 illustrates conveyor system 400 having acurved divert track section 403 with permanent magnets 450 and/or withdiverter/transfer coils 451 on the divert track section and a pluralityof moving elements 404 with ferromagnetic plates 430 on one side andmagnetic elements 428 on a reverse side. Two track sections 402A and402B are also visible and include magnetic coils 452 which attract themagnetic elements 428 toward the track sections 402A and 402B, by, forexample, dynamic lateral magnetic forces. By varying the strength andpolarity produced by the magnetic coils 452 (and possibly coils 451),the moving elements are able to travel either by continuing on a firsttrack section 402A or be diverted via the curved divert section 403 tothe second track section 402B. In this case, the moving elements 404 canbe seen travelling on a track section 402 and being biased toward thedivert track section 403 via the attraction between a ferromagneticplate 430 of the moving element 404 and the permanent magnets 450 and/orcoils 451 of the divert section 403.

In some cases, the linear motor conveyor system may include a tracksection having a linear motor and a divert section having anelectromagnet that may generate the lateral force for the diversion. Instill other cases, a second magnetic field may be associated with atrack and/or divert section to provide a further field strengthening orfield weakening. For example, an external electromagnet or othermagnetic element may be paired with a divert section or track section toprovide for further forces (such as lateral forces) generated from theinteraction of the moving element with the track and divert section.

In some cases, diversion may be aided or accomplished by settingdifferent magnetic gap sizes between the rails, which may help balancestatic magnetic forces or bias the moving element toward one rail. In anexample shown in FIG. 7, a guide rail in a track section 502 may have afirst magnetic gap (MG1), and a guide rail on a divert section 503 mayhave a second magnetic gap (MG2). The magnetic gaps may be defined by acombination of physical distances and cumulative magnetic forces. Forinstance, the physical size of the first magnetic gap MG1 might begreater than the second magnetic gap MG3 but the magnetic force of thesecond magnetic gap MG2 might be greater than the first magnetic gapMG1, which may result in equivalent magnetic gap sizes, as explained infurther detail below.

In some embodiments, a difference in magnetic gap, as MG1 is less thanMG2, can help bias a moving element 504 toward the first rail as a forceF1 is intended to be sufficiently greater than a force F2 to bias themoving element toward the first rail. In a specific example, a force of200 N toward first rail minus 160 N force toward second rail results ina 40 N net bias force toward first rail. Adjusting the size of the gapand/or the force of the magnetic fields may bias the moving element inthe desired path, for example to continue on the track section or divertto the divert section. In addition or alternatively, the size of the gapand/or the static force of the magnetic fields could help reduce theamount of dynamic magnetic force needed to divert the moving elementbetween rails. In the example above, the dynamic magnetic force requiredto cause a diversion is on the order of 40 N. If the second force of 160N were not present, then a 200 N dynamic magnetic force would berequired. In some cases, the first magnetic gap may be in a range ofapproximately 1 mm to 3 mm and the second magnetic gap may beapproximately 0.1 mm to 1 mm different from the first magnetic gap.

It is worthwhile noting that the need to overcome static magnetic forcesis more important when the moving elements are held on the rail withlateral magnetic forces. On systems with mechanical wheel encapsulation,there might be lower lateral magnetic forces, and, thus, the dynamiclateral magnetic forces required might already be relatively small

In addition to the magnetic gap, otherwise referred to as a motor gap,there may also be a physical rail gap. The physical rail gap determineshow far the wheels shift laterally. The magnetic gaps are intended toset the lateral magnetic forces and the resulting imbalance to beovercome in the case of diverting. Physical rail gap may be consideredas a conventional mechanical adjustment which may be set prior todetermining the magnetic gaps. The magnetic gaps are intended to be setindependently of the physical rail gap to achieve a balanced magneticforce to accommodate diversion or the transferring of the movingelements.

In some cases, a setup tool 600 may be used to assist with setting upthe moving elements so that magnetic tolerances for the conveyor systemare set appropriately as described herein. An embodiment of a setup toolis shown in FIGS. 8A and 8B. As noted above, a conveyor system having atransfer/branching/divert option may be based on magnetic fieldstrengthening and/or weakening which may require tight tolerances in themagnetic gaps as the moving element is transferred from one motor overto a receiving motor, for example when a moving element moves between atrack section and a divert section. In this type of arrangement,multiple mechanical stack-up tolerances in both the moving element andthe track may be combined into a resulting magnet gap tolerance (relatedto the distance between magnet and driving element). It can be costly tohold all parts to tight tolerances in order to achieve an appropriatemagnet gap tolerance for efficient operation of the system. Further, itmay also be difficult to align motors/driving elements at diversionpoints if the alignment tolerances are required to be very tight.Further, permanent magnets are known to have inherent variation inmagnetic field strength which may add a further complication whendealing with moving elements having two magnetic elements or sets ofmagnetic elements.

It is intended that the manufacturing tolerances for both the conveyorsystem and the moving element are in a range that allow the parts to becost effective to manufacture. It is also intended that the tolerancesto align two driving elements/motors on a system for diversion arereasonable for ease of system assembly. In each moving element, themagnet or magnets are ideally adjusted to be aligned well enough thatmoving elements divert reliably in either direction, orientation and atany speed as controlled by the controller. In working with manufacturingtolerances, it was determined that, in some cases, it may be preferableto adjust or calibrate mechanical parts based on magnetic field strengthversus manufacturing tolerances. In particular, it was determined thatmagnetic field strength may be considered a basis for reliable diversionbased on the embodiments described herein. Overall, the followingcalibration processes may be referred to as calibrating the staticmagnetic forces between the moving elements and the track sections.

FIGS. 8A and 8B show an embodiment of a setup tool 600 that could beused to adjust the magnet gap at a diverter location based on magneticfield strength while FIG. 8C illustrates an overhead view of the setuptool 600 as it would appear between two track sections (for example, atrack section and a divert section). This tool 600 has a magneticelement, such as a permanent magnet or a permanent magnet array (similarto the permanent magnet or magnet array on the moving element) that isattached to a load cell configured to measure force. This tool 600 isconfigured to be brought into position at a diverter location and movedthrough the divert area so that the permanent magnet/magnet array wouldinteract with one of the motor stators in the conveyor system. Since thepermanent magnet is attached to the load cell, the load cell isconfigured to report the actual magnetic attractive force, in oneembodiment, on a display (not shown). The magnet gap can then beadjusted to achieve a predetermined magnetic force for reliablediversion by adjusting the settings for the track section and/or divertsection accordingly. The setup tool 600 may then be rotated 180 degreesand the procedure repeated to set the gap for the opposing motor beingused for diversion. Adjusting the two magnet gaps based on magnetic(e.g. attractive) force may be easier and more reliable thatmanufacturing or adjusting to precise manufacturing tolerances. Ingeneral, the manufacturing tolerances of all of the parts thatcontribute to magnet gap variability may not have to be held as tight ina situation where the magnet gaps can be adjusted based on magneticforce. This approach can also be used to at least somewhat compensatefor variability in permanent magnet strength.

As shown in FIGS. 8A and 8B, it is intended that the setup tool includeat least one shaped spacers such as bearing 624 and one flat spacer suchas bearing 626 intended to correspond to the guide rails of the conveyorsystem. In general, the setup tool is intended to be similar to theformat of a typical moving element as used on the conveyor system. It isintended that bearings may allow the setup tool 600 to conveniently rolland traverse the guide rails. While wheeled bearings are shown, thespacers could be machines profiles formed along the tool that correspondto the guide rails, in which case, the machined profiles may have lowfriction coatings such as Teflon™. In general, the setup tool isintended to be similar to the format of a typical moving element as usedon the conveyor system.

Generally speaking, an example embodiment of a process to adjust therail and the magnet/air gap at the same time could include the followingprocesses and make use of an embodiment of a setup tool such as thatdescribed above.

First, the physical gap between the two track sections and the height ofthe rails for each of the track sections at a diversion point is setmechanically. In this embodiment, the setup tool has laterally offsetwheels in order to set the physical spacing of the rails before settingthe magnetic gap.

The setup tool is brought into the diversion location and the rails ofeach track section are adjusted to butt up against the wheels of thesetup tool on both sides. In particular, the lateral wheel offset setsthe physical gap between the rails. As noted, the height of the rails ofeach track section is also adjusted by ensuring the V-wheels of thesetup tool are fully engaged on both sides and the top of the movingelement is level.

With the setup tool located at the diversion location, the load cell ofthe setup tool will measure the magnetic attraction force to one of thetwo motors. This motor is then adjusted to achieve a set point forcewithout moving the rails. The configuration profile may be stored in ahardware or software controller or in a memory therein or associatedtherewith. In this way, the motor/magnetic gap is based on a magneticforce, not a physical dimension.

The setup tool is then rotated 180 degrees and placed at the diversionlocation. The same step is then applied to the opposing motor to adjustthe motor to achieve the appropriate set point magnetic force.

At this point, both the physical and magnetic gaps have been adjusted sodiversions should function smoothly when passing from either motor tothe other motor in either direction of travel.

In general, the magnetic element or magnetic elements in the movingelement are intended to be mounted as appropriate for diversion to workreliably in either direction, with either moving element orientation,across all moving elements and diverters on the system. In this case, anembodiment of a stationary setup tool 700 intended for a moving elementwith two magnetic elements is shown in FIGS. 9A and 9B. This embodimentof the stationary setup tool is configured in a similar way as a portionof the track but is provided with a steel plate attached to a load cell710 in a location where the linear motor would otherwise be mounted.

The stationary setup tool may be provided with rails that are similar tothose on a track section so a moving element may be placed in front ofthe steel plate, which is intended to mimic the motor stator. The loadcell measures the attractive force of the magnetic elements in themoving element and from this an offset may be calculated to adjust themagnetic elements within the moving element to a magnetically calibratedposition using a magnet positioning 810 device such as that shown inFIG. 10. The magnet positioning device 810 may include one or more shims812 (as shown in FIG. 10), a ground datum, set screws or the like, withthe goal of positioning the magnetic element to achieve the appropriateforce during movement and diversion. In some embodiments, there may be amagnet positioning device for each magnetic element on the movingelement. After adjustment of the magnetic element on one side, themoving element may be flipped and the second magnetic element would beadjusted appropriately following the same procedure. The moving elementwill then be configured such that both magnetic elements are alignedbased on magnet attractive force and manufacturing tolerances are nolonger as critical. Again, this approach is also intended to assist withcompensation for variability in magnet strength in the case wherepermanent magnets are used. All moving elements can be setup to providean appropriate magnetic force for reliable diversion.

It is intended that the linear motor conveyor system provided herein mayinclude flexible, high speed diverters that enables high volumeproduction without processes having to follow a conventional assemblyline order (i.e. allow for diversion through differing processes, inparallel or other processing formats).

Conventionally, assembly lines still generally follow very earlyconcepts of serial processing (i.e. having one station after the otheron a line, without diversion to other lines or processes). Conventionaldiverters exist but they are generally slow, take up significant space,require complex mechanical connections, have constraints where they canbe located, have moving parts that wear and require maintenance and arecostly. As noted herein, diverters for linear motor conveyors have beenparticularly difficult because of the forces involved and the need formechanical tooling, actuators or the like. As a result of theseconstraints, conventional diverters are used to enhance the serialassembly line but they do not change the overall paradigm. For example,diverters may be used to route product to multiple stations doing thesame process (partially parallel) and back to the main line which mayall still be done in serial. Diverters may also be used to route defectproduct off a line and, after repair, the product can be routed backonto the line to continue from where it left off in the serial process.Current diverters add flexibility to the serial assembly line but haveconstraints that prevent organizing processes in alternate ways.

FIGS. 11A and 11B illustrate a conveyor system 400 which includesexamples of diverters. The intention is to route moving elementson-the-fly at operating speeds so that the diverting will allowcontinuous flow of moving elements. In a manufacturing environment, itis intended that the diverters be highly reliable to handle manydiversions per shift as a normal mode of operation. For example, in atypical manufacturing environment, the diverters may handle anywherefrom 30 to 800 diversions per minute (or any value in between) under24/7 operation which is equivalent to millions of diversions per week.The diverters are intended to be compact, cost effective, available tobe added almost anywhere in the conveyor system, operate bidirectional,operate at programmable speed, and the like. It is intended that thecontrol system for the conveyor system takes care of any complexities oftraffic control. Conveyor systems using these diverters may beconfigured in flexible ways such that combinations of curves andstraight track sections may be configured as needed for variousapplications. Ideally, the track sections are also modular and can bereused or reconnected again if there is a reconfiguration of theconveyor system. Large conveyor systems may also have regions or zonesat different physical heights so the linear motor conveyor may also haveelements allowing the conveyor system to adjust to varying heights.FIGS. 12A and 12B show example embodiments of conveyor tracks that movefrom one height to another.

It is intended that the divert allows the conveyor system to have curvedtrack sections with integrated straight profiles which allows fordiverts on the curved track section. Conventionally, linear motorconveyor systems have a curved track section and a short track sectionto enable divert which was intended to provide for greater versatility.It has been found though that having a separate short track section maybe undesirable. It was noted that having a separate short track sectionrequired mechanical joints and transitions that may be hard to align andincrease cost while reducing reliability. Curved sections withintegrated straight profiles do not require extra joints which mayimprove the reliability. It was also noted that separate track sectionsmay require separate controls and increase controller and wiringcomplexities. The divert system and method described herein are intendedto provide for integrated curves which may reduce these additionalcomplexities.

As indicated herein, it is intended that the divert operation beaccomplished by varying the magnetic field to the moving element as itmoves through a divert. As such, it is intended that no additionalmechanical actuations are required for diversion, just magnetic fieldadjustment. As there are no mechanical actuations, the diversion isintended to be highly reliable over a very large number (possibly, manymillions) of diversions in a normal mode of operation.

In the embodiments herein, the same magnetic elements, for example themotors/drive elements (and, in particular, the coils in the motors), maybe used for both propulsion and diversion, which is intended to allowdiversion to occur anywhere along the linear motor. Diversions areintended to occur at programmable speed and may be bidirectional forflexibility in configuring the conveyor system and track sections.

Further, since in the embodiments herein, standard linear motors canperform the diversion without additional coils, electronics ormechanical actuations, the solution is intended to be cost effective andcompact.

As noted herein, the conveyor system and/or each divert location mayinclude a controller which is intended to provide traffic control andprevents collisions. The controller may also be configured to attempt toavoid moving element lockups or the like, which may occur in a situationinvolving flexible, non-serial flow.

FIGS. 13 and 14 illustrate a method of designing conveyor systems thatinvolves organizing standardized parts on a grid to allow conveyorsystems to be configured in flexible ways using various combinations ofcurved and straight track sections. A conventional system of designingconveyor systems involves organizing the conveyor on a grid in which thecenter-line of the conveyor is on the grid. In the case of designinglinear motor conveyors, this approach has generally been maintained.This has been problematic for linear motor conveyors that have themoving element on a side of the track as opposed to on top of the track(which is the configuration of many conventional conveyor systems). Inan unexpected development, it was determined that, if the movingelements are placed/centered on the grid (as opposed to the tracksections or other datum), conveyor systems can be designed that will beable to be connected and reconnected much more easily.

One of the benefits of designing with the moving element on the grid ismodularity. In particular, a small series of building blocks can be madethat allow systems to be put together of many different shapes andconfigurations. This modularity extends from the track itself, to otherrelated elements including shrouding, table tops, table frames andoutriggers, as well as guarding equipment that may be arranged aroundthe conveyor system. With the moving elements on the grid, flexibleshapes of the track can be defined and then the complete system,including guarding can be generated such that all componentsinterconnect efficiently and accurately. If moving elements are not ongrid, any design beyond that of a basic carousel, requires additionalplanning/design because of irregular geometry. In this situation, layoutflexibility is constrained and all the table and guarding design mustgenerally be carried out on a semi-custom basis, requiring many moreunique parts.

As noted and shown herein, in some cases, the conveyor system mayinclude zones of different heights. It may be beneficial to includevarious zones at different heights as this may allow for larger,multi-zone systems. In some cases, it should be possible to raise orlower moving elements on-the-fly without degrading throughput. It hasbeen found that the use of a grid system with the moving elements on thegrid lines allows for the more efficient design of multi-level conveyorsystems.

In the embodiments herein, while the conveyor system is shown with thetrack in an upright or vertical orientation and the moving elements onthe side, it will be understood that the conveyor system may be in anydesired orientation while achieving at least one advantage describedherein.

FIG. 15A illustrates a moving element 1004 having a first set ofbearings 1024 with a shaped profile, a second set of bearings 1026 witha flat profile, a body 1020, and two magnetic elements 1028 located oneither side of the body 1020. During operation, there may be a desire tohave further stabilization for the moving element 1004, especially whenthe load of the moving element 1004 is not centered. In some cases, oneor more stabilizers 1030A and 1030B may be included on the movingelement 1004. In this embodiment, the stabilizers 1030A and 1030B arespaced apart from the rails by a small gap, and only contact the railsif the pallet rotates off the track. In some cases, the stabilizer 1030may be mechanical restraints that are intended to reduce rotation duringa divert section. In some cases, mechanical restraint(s) may beadditional bars located above and below the first set of bearings 1024and configured to be proximate to the first guide rail of both the tracksection and divert section of the conveyor system, but may allow for asmall gap between the stabilizers 1030 and the track and/or divertsection. If the moving element 1004 experiences rotation during thediversion, the stabilizers 1030 are intended to abut against the surfaceof the track section and/or divert section to stabilize the movingelement 1004. In some cases, stabilizers may be included only above oronly below the first set of bearings 1024.

FIGS. 15B and 15C illustrate the moving element 1004 on a track section1002 approaching a divert section 1003 and in between the track section1002 and divert section 1003. Unlike conventional conveyor system thattraditionally encapsulate the moving element throughout the movingelements travel, the linear conveyor system detailed herein encapsulatesthe moving element only during a divert section. It was determined thata stabilizer may be beneficial during the divert sections to reduce oreliminate rotation of the moving element as it is biased between thetrack section and the divert section.

Stabilizers can be useful in the diverter section because of reducedstatic lateral forces holding the moving element on the rail. Using theprevious example, normally the pallet is suspended to the motor withapproximately 200 N lateral force. In the diverter region the lateralholding forces may be reduced to approximately 40 N due to balancing ofthe static lateral force between the first and second guide rails.Without the stabilizers, the moving element could rotate more easily dueto lower holding force. The possibility of tipping increases if there isacceleration or deceleration of the moving element, or if the payload onthe moving element is off-center. Thus, the stabilizers may prevent orinhibit rotation throughout the diverter region, and can provide addedsafety during the actual diversion motion and as the pallet is movingthrough the diverter area. Typically the stabilizers do not make contactunder normal operation and just make contact when an undesired rotationoccurs.

FIG. 16 illustrates an alternative embodiment of a moving element 1104having a first set of bearings 1124 with a shaped profile, a second setof bearings 1126 with a flat profile, a body 1120, two magnetic elements1128 located on either side of the body 1120, and a stabilizer bearings1130A and 1130B located at the top and the bottom of the moving element.In some cases, the stabilizers may only be located at the top, or onlylocated at the bottom of the moving element. The bearing stabilizers1130A include a plurality of wheels which are intended to providesupport and greater stability to the moving element 1104 during thediversion from a provide support on the top surface of a first guiderail. The bottom bearings of the stabilizer are intended to providesupport on the bottom surface of a second guide rail. During normaltravel, the stabilizer bearings 1130 may be proximate but may not abutagainst either guide rail. The stabilizer bearings 1130 may beconfigured to make contact with either the first or second guide rail ifthe moving element 1104 experiences rotation and, if there is contact,it may generate less friction compared with the moving element 1004 inFIGS. 15A to 15C.

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe embodiments. However, it will be apparent to one skilled in the artthat these specific details may not be required. In other instances,well-known structures are shown in block diagram form in order not toobscure the understanding. For example, specific details are notprovided as to whether some of the embodiments described herein areimplemented as a software routine running on a processor via a memory,hardware circuit, firmware, or a combination thereof.

The above-described embodiments are intended to be examples only.Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art without departingfrom the scope, which is defined solely by the claims appended hereto.

What is claimed is:
 1. A linear motor conveyor system comprising: amoving element comprising a first magnetic element on a first side and asecond magnetic element on a second side, opposite to the first side; afirst track comprising a first linear motor, the first linear motorconfigured to generate a dynamic magnetic field which acts on the firstmagnetic element to provide both a first dynamic lateral force and afirst dynamic longitudinal force on the moving element; a second trackwith at least a transfer region of the second track positioned adjacentthe first track, the second track configured to generate a magneticfield that acts on the second magnetic element to provide a secondlateral force on the moving element; and a controller to control atleast the first linear motor such that the first dynamic lateral forcefrom the first linear motor and the second lateral force from the secondtrack are configured to bias the moving element toward the first linearmotor until the moving element reaches a switch point in the transferregion, after which the dynamic lateral forces are selectively adjustedsuch that the second lateral force overcomes the first lateral force tobias the moving element toward the second track.
 2. A linear motorconveyor system according to claim 1, wherein the first track comprisesa first magnetic material which acts on the first magnetic element toprovide a first static lateral force in addition to the first dynamiclateral force, wherein the controller adjusts the first static lateralforce in addition to the first dynamic lateral force.
 3. A linear motorconveyor system according to claim 2, wherein the second track comprisesa second magnetic material which acts on the second magnetic element toprovide a second static lateral force, and wherein the controllerselectively adjusts the first dynamic lateral force to bias the movingelement toward the first track or the second track by overcoming netstatic forces from the first and second static lateral forces.
 4. Alinear motor conveyor system according to claim 3, wherein the firststatic lateral force is set based on a first magnetic gap between themoving element and the first linear motor, and the second static lateralforce is set based on a second magnetic gap between the moving elementand the second linear motor.
 5. A linear motor conveyor system accordingto claim 4, wherein the second track comprises at least oneelectromagnet and the first dynamic longitudinal force is configured topropel the moving element along the second track while held to thesecond track by the lateral forces of the at least one electromagnet. 6.A linear motor conveyor system according to claim 1, wherein the movingelement further comprises at least one cover for at least one of themagnetic elements to shield the magnetic field.
 7. A linear motorconveyor system comprising: a moving element comprising at least onemagnetic element; a first track comprising a first linear motor, thefirst linear motor configured to have a first predetermined magnetic gapbetween the first linear motor and the moving element to bias the movingelement toward the first linear motor; a second track having at least atransfer region positioned adjacent the first track such that the movingelement has a second predetermined magnetic gap between the second trackand the moving element; and a controller to control the first linearmotor such that, in the transfer region, the first linear motor can beselectively adjusted to generate a lateral magnetic force that, incombination with the second predetermined magnetic gap, overcomes thefirst predetermined magnetic gap and biases the moving element towardsthe second track.
 8. A linear motor conveyor system according to claim7, wherein the second predetermined magnetic gap is different from thefirst magnetic gap.
 9. A linear motor conveyor system according to claim7, wherein the moving element comprises a first magnetic element on afirst side and a second magnetic element on a second side, opposite tothe first side.
 10. A linear motor conveyor system according to claim 9,wherein the second track comprises at least one electromagnet and thefirst dynamic longitudinal force is configured to propel the movingelement along the second track while held to the second track by thelateral forces of at least one magnetic element.
 11. A moving elementfor a linear motor conveyor system, the moving element comprising: atleast one magnetic element having a magnetically calibrated position inrelation to the moving element and configured to interact with both amagnetic field generated by a first linear motor on a first track and amagnetic field associated with a second track to bias the moving elementtowards the second track when the magnetic field associated with thesecond track overcomes the magnetic field generated by the first linearmotor.
 12. A moving element according to claim 11, further comprising: amagnet positioning device for adjusting position of the magneticelement.
 13. A moving element according to claim 11, wherein the atleast one magnetic element comprises a first magnetic element on a firstside and a second magnetic element on a second side, opposite to thefirst side.
 14. A moving element according to claim 11, furthercomprising a stabilizer configured to reduce rotation of the movingelement.
 15. A moving element according to claim 11, further comprisingat least one cover for at least one of the magnetic elements to shieldthe magnetic field.
 16. A method of configuring a diverter on a linearmotor conveyor system, the method comprising: physically mounting afirst linear motor track adjacent a second track at a predetermineddistance; determining the magnetic forces on a setup tool placed betweenthe adjacent tracks; and adjusting a magnetic set point for each of thefirst and second tracks based on the determined magnetic forces to allowa moving element to be diverted from the first track to the second trackwhen a magnetic force associated with the second track overcomes amagnetic field generated by the first linear motor track.